C4 is involved in the classical activation pathway of the complement system and is often measured alongside C3. Low C4 is characteristic of active systemic lupus erythematosus, hereditary angioedema, and other immune complex-mediated diseases. Like C3, C4 falls during active autoimmune disease as it is consumed by ongoing inflammation.
This test is ordered to evaluate suspected lupus or other autoimmune diseases, monitor disease activity, work up patients with recurrent angioedema (where low C4 supports hereditary angioedema), and investigate certain glomerulonephritis. Sample type is serum.
We are CLIA certified, the highest level of Medical industry compliance and standards.
Book an appointment